Production Blog

Dig into Dicamba Details

Pam Smith
By  Pam Smith , Crops Technology Editor
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A repeat performance of off-target movement is not what the agriculture industry needs to see in 2018. (DTN photo by Jim Patrico)

DECATUR, Illinois (DTN) -- Over the past few weeks, DTN has flooded readers with details on dicamba. Our series of articles was intended to provide simplified reminders of the complex details required to spray Engenia, FeXapan and XtendiMax herbicides.

We based the articles on the five avenues the EPA identified by which dicamba herbicides moved off-target last year: physical drift, tank contamination, misuse, temperature inversions and volatility.

The series was not intended as a statement of support or criticism of the Xtend production system. Nor was it written to encourage farmers to use more dicamba.

The series was a simple acknowledgement that there will be more dicamba-tolerant soybeans and cotton across the landscape in 2018. Monsanto has estimated the dicamba-tolerant trait will be planted on 40 million acres of soybeans alone.

We are service journalists. Given the issues with off-target movement in 2017 and statements by registrants that applicators were not adequately educated to use the products, it is our responsibility to flush out more details.

According to Monsanto's Ryan Rubischko, dicamba product manager and marketing lead, more than 81,000 applicators participated in some type of dicamba training over the winter.

Let's hope this training helps. No one wants a repeat of last summer.

Unfortunately, this week I've already fielded several calls regarding concern about the use of dicamba in a pre-plant burndown on soybean. The Illinois Fertilizer and Chemical Association issued a reminder about the need to follow labels and pre-plant precautions. Even when planting dicamba-tolerant soybeans, only Engenia, FeXapan and XtendiMax can be used in an immediate pre-plant situation.

The new labels EPA established are complex and restrictive. There are many that feel applying the products in full accordance with the label, while still accomplishing weed control, may be not be possible.

Still, the need to do everything you can to use this technology properly has never been greater. The conditional labels on Engenia, FeXapan and XtendiMax are up for renewal this fall.

To factor physical drift and volatility concerns into spray applications, consider some of these suggestions from Ohio, Indiana and Illinois weed scientists:

-- Watch the wind. Federal labels stipulate spraying when wind speeds are between 3 and 10 mile per hour. In 2017, many applicators focused on average wind speed and did not factor in gusts.

-- Lower the boom. A 24-inch boom height limit is specified on the label. Reducing boom height from 48 inches to 24 inches can reduce the distance particles travel by 50%. Slow down to avoid running the boom into the ground -- the label stipulates a ground speed limit of 15 mph and recommends 5 mph around field edges.

-- Build a buffer. Last year many applicators decided to apply dicamba right next to the sensitive crop if the wind was blowing the opposite direction. However, wind directions change and University research shows even the new formulations can volatilize and move for up to three days following application.

-- Take Temperature readings. Avoid applications when temperatures exceed 80 degrees Fahrenheit. Warmer weather increase the likelihood of the herbicide to become more volatile.

-- Apply Early Season. Consider applying dicamba preplant, preemergence, or very early postemergence when temperatures are more likely lower. Early spring applications are less likely to cause injury even where dicamba moves since there's less developed vegetation.

-- Spray by Day. The labels specify the applicator must ensure a temperature inversion does not exist. Most labels limit spraying to between sunrise and sundown, although some states have set specific application hours. The minimum 3 mph wind speed are also in place to help avoid inversions.

-- Adjust Additives. Never add anything to the tank that is not specifically approved on the product website. Avoid adding anything containing ammonium sulfate (AMS), which converts dicamba to more volatile forms. There are approved non-ammonium sulfate-based water conditioners to reduce hard water antagonizing glyphosate that is tank-mixed with an approved dicamba formulation.

-- Know the neighborhood. Have conversations with neighbors to know what crops and technologies are being planted around Xtend fields. Applicators are required by label to show they surveyed the surrounding area.

-- Keep complete records. Record keeping must be done for every Engenia, FeXapan and XtendiMax application (regardless of crop sprayed) and for each individual field.

-- Know your state requirements. Some states have requirements that go beyond or differ from federal labels.

Review further details at these training sites for herbicides approved to use with the Xtend crop system:

https://www.engeniastewardship.com/…

http://cloud01.bader-rutter.com/…

http://www.roundupreadyxtend.com/…

To read the articles in the Dicamba Details series go to:

Dicamba Details — 1, Decision Time for Dicamba

https://www.dtnpf.com/…

Dicamba Details — 2, Let's Get Physical -- How Does Particle Drift Happen?

https://www.dtnpf.com/…

Dicamba Details - 3, Clean Up Your Act

https://www.dtnpf.com/…

Dicamba Details - 4, The Most Common Types of Off-Label Dicamba Use

https://www.dtnpf.com/…

Dicamba Details - 5, Temperature Inversions Make Evening Applications Risky

https://www.dtnpf.com/…

Dicamba Details - 6, Don't Dismiss Volatility

https://www.dtnpf.com/…

Pamela Smith can be reached at Pamela.Smith@dtn.com

Follow her on Twitter @PamSmithDTN

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